JPS60174291A - Laser irradiating device - Google Patents

Abstract

PURPOSE:To maintain the optical axis of laser light always at a specified angle with an object by providing two sheets of mirrors in an optical path for the laser light and moving respectively rectilinearly the mirrors in different directions thereby scanning the laser light. CONSTITUTION:Laser light 2 irradiated in an x-axis direction by a laser oscillator 1 is reflected in a y-axis direction by the 1st mirror 15 and is further reflected in a z-axis direction by the 2nd mirror 16 so that the reflected light is made incident on a substrate 3. Since the mirror 15 moves in the x-axis direction, the light 2 scans on the substrate 3 at the speed thereof. The mirror 16 is then moved in the y-axis direction to irradiate the light 2 over the entire surface of the substrate 3 on a supporting table 4. The irradiating angle of the light 2 is maintained constant by small driving power without moving the table 4 according to such mechanism. The device is usable for melting by heating or cutting by heating, etc. of a semiconductor, etc.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a laser beam irradiation device for performing processing such as heating melting or heating cutting by scanning and irradiating a workpiece such as a semiconductor with a laser beam. It is related to.

[Prior art]

Generally, in order to realize high-speed, high-density semiconductor devices,
Attempts have been made to form a single-crystal semiconductor on an insulator and to fabricate an element in this semiconductor layer. In order to form a single-crystal semiconductor layer on the insulator, a narrowly focused laser beam is scanned and irradiated onto the semiconductor layer heated to about 400 degrees Celsius, melting the semiconductor layer and turning it into a single crystal. There is a way to do it.

Conventionally, there have been two types of laser beam irradiation apparatuses shown in FIGS. 1 and 2 as laser beam irradiation apparatuses for melting this semiconductor layer. In Figure 1, 1 is a laser oscillator, 2 is a diameter of several tens of microns.
3 is a semiconductor substrate having a semiconductor layer formed on an insulator, and 4 is a support base that supports the semiconductor substrate Ifi3 and heats it to about 400°C. This support stand 4 is movable in a plane perpendicular to the laser beam 2 (in the x and X directions in the figure) so that the laser beam 2 is always perpendicularly incident on the semiconductor substrate 3.

As shown in FIG. 1, the support table 4 is moved in the X direction at a speed of several tens of cm/sec within a plane perpendicular to the laser beam 2. Therefore, the surface of the semiconductor substrate 3 is scanned by the laser beam 2 in the X direction at a speed of several tens of degrees per second. And when this -scanning is finished,
The support table 4 is moved several tens of μm in the X direction, and the next scan in the X direction begins. In this way, the semiconductor substrate 3 on the support base 4 is
The entire surface of the semiconductor layer is irradiated with laser light, and the semiconductor layer is heated and melted.

Single crystallization is performed.

FIG. 2 is a schematic diagram of another conventional laser beam irradiation device.

In the figure, the same reference numerals as in FIG. 1 indicate the same parts. 5
and 6 is the first one equipped with a galvanometer. The second mirror can be rotated in the X direction and in the X direction perpendicular to it.

The first mirror 5 rotates so that the laser beam 2 is scanned over the semiconductor substrate 3 in the X direction at a speed of several tens of cm/sec. When the laser beam 2 finishes the constant distortion in the X direction on the semiconductor substrate 3, the second mirror 6 rotates so that the laser beam 2 moves several tens of μm in the X direction, and then the first mirror 5 starts rotating for the next scan in the X direction. In this way, the entire surface of the semiconductor substrate @3 on the support base 4 is irradiated with laser light, and the semiconductor layer is heated and melted and made into a single crystal.

However, in the conventional apparatus shown in FIG. 1, in order to irradiate the entire surface of the semiconductor layer with laser light, a heavy support base 4 equipped with a heating device must be moved, which requires a large amount of power. There were drawbacks such as the complexity of the device. Furthermore, although the conventional device shown in FIG. 2 is simpler than the device shown in FIG. 1, the laser light is not always irradiated onto the semiconductor layer at the same angle. When an antireflection film is attached thereon, there is a drawback that the power of the laser light absorbed by the semiconductor layer varies depending on the location and is not constant.

[Summary of the invention]

This invention eliminates the above-mentioned drawbacks of the conventional method, and by scanning the laser beam, the optical axis of the irradiated laser beam always maintains a constant angle with respect to the object. Another object of the present invention is to provide a laser beam irradiation device that does not require large power to scan the laser beam.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. Third
5 to 5 show a laser beam irradiation device according to an embodiment of the present invention. In the figures, ■ is a laser oscillator that emits continuous wave laser beam 2;
For example, argon (Ar) gas laser light and carbon dioxide (CO2) gas laser light are used. 15.1
Reference numeral 6 denotes a first . The first mirror 15 is a second mirror, and the first mirror 15 is oriented 45 degrees in a horizontal plane with respect to the optical axis (X-axis) of the laser beam emitted from the laser oscillator 1,
It is arranged perpendicularly to the surface of the semiconductor substrate 3. Further, the second mirror 16 is arranged so that its longitudinal direction is parallel to the X-axis, and is inclined at 45 degrees in a plane perpendicular to the optical axis (X-axis) of the reflected light from the first mirror 15. The laser beam reflected from the first mirror 15 is reflected in two axial directions. And the first of these. The second mirrors 15 and 16 are movable linearly in the X-axis direction and the Y-axis direction, respectively, by chain drive means (not shown). Note that the surface of the semiconductor substrate 3 is the first. second mirror 15
．． 16 in a plane parallel to the moving directions x and y, that is, in a plane perpendicular to the z-axis.

Next, the operation will be explained.

The laser beam 2 emitted from the laser oscillator 1 in the X-axis direction is reflected by the first mirror 15 in the y-axis direction, and the reflected laser beam is further reflected in two-axis directions by the second mirror 16 to strike the semiconductor substrate. It is incident perpendicularly to 3. At this time, the above first
Since the mirror 15 is moving at a speed of several tens of meters/sec in the X-axis direction, the laser beam 2 is scanned on the semiconductor substrate 3 at a speed of several tens of cm/sec in the X-direction. Become. When the laser beam 2 completes one scan in the X-axis direction on the semiconductor substrate 3, the second mirror 16 moves several tens of μm in the Y-axis direction, and the irradiation position of the laser beam 2 on the semiconductor substrate 3 changes by several tens of μm. Moving. Then, the next scan in the X-axis direction, that is, the movement of the first mirror 15 begins again. In this way, the entire surface of the semiconductor substrate 3 on the support stand 4 was covered with it. A laser beam is irradiated to heat and melt the semiconductor layer and make it into a single crystal.

The irradiation angle of the laser beam irradiated onto the semiconductor substrate 3 is always constant over the entire surface of the substrate 3, resulting in uniform heating and melting.
Single crystallization can be performed. Further, there is no need to move the support base 4 as in the conventional device, and the power required for the device can be significantly reduced.

In the above embodiment, the laser beam is made to enter the surface of the object perpendicularly, but it may be made to enter the object obliquely, and the same effect as in the above embodiment can be obtained. Furthermore, the first mirror that is movable in the X-axis direction and the second mirror that is movable in the Y-axis direction may be made stationary at the same time.

〔Effect of the invention〕

As described above, according to the present invention, in a laser beam irradiation device that scans a laser beam and irradiates an object with it, two mirrors are provided in the optical path of the laser beam, and these mirrors are directed in different directions. Since the laser beam is scanned by moving the laser beam in a straight line, the irradiation angle of the laser beam irradiated onto the object can be kept constant, and the power required for laser beam scanning can be extremely reduced. effective.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing an example of a conventional laser beam irradiation device.
FIG. 2 is a schematic diagram showing another example of a conventional laser beam irradiation device, FIG. 3 is a schematic diagram showing a laser beam irradiation device according to an embodiment of the present invention, and FIG. 4 is a plan view of the device in FIG. 3. 5 is a side view of the apparatus of FIG. 3. 1... Laser oscillator, 2... Laser beam, 3...
Semiconductor substrate (object), 15...first mirror, 16...
・Second mirror. Note that the same reference numerals in the figures indicate the same or equivalent parts. Applicant Kawa, Director of the Agency of Industrial Science and Technology ■1 Hirobe Figure 1 Figure 2 Figure 1 Figure 3 Figure 5

Claims (4)

[Claims] (1) In a laser beam irradiation device that scans a continuous wave laser beam emitted from a laser oscillator and irradiates it onto an object, a first laser beam provided in the optical path of the laser beam from the laser oscillator to the object. ．． a second mirror; and the first mirror. Second
a chain driving means for linearly moving each of the mirrors in mutually different directions to perform scanning with the laser beam. (2) The first mirror is arranged at an angle of 45° in a horizontal plane with respect to the X-axis, which is the optical axis of the laser beam emitted from the laser oscillator, and the second mirror is arranged along its longitudinal axis. The chain driving means is arranged so that its direction is parallel to the X-axis and is inclined at 45° in a plane perpendicular to the y-axis, which is the optical axis of the reflected light from the first mirror. 1. The second mirror is moved linearly in the X-axis and y-axis directions, respectively,
The light incident on the object, which is the reflected light from the second mirror, is Z
The laser beam irradiation device according to claim 1, characterized in that the laser beam irradiation device is oriented in the axial direction. (3) The laser light irradiation device according to claim 1 or 2, wherein the laser oscillator emits argon gas laser light. (4) The laser light irradiation device according to claim 1 or 2, wherein the laser oscillator emits carbon dioxide gas laser light.